The present invention relates to electricity conductors and insulators and, more particularly, to electric device boxes and housings and mounting means therefor.
The ability to quickly repair or replace a defunct switch is a highly desirable characteristic in many applications. For example, in bank alarm systems, switches are typically used to trigger an alarm or turn on a camera, e.g., at each teller station. It is not unusual for each switch to be in a constantly activated state in which it is always carrying an electric current. If the current is interrupted, such as when the switch is pressed or fails, or when the switch""s wiring is cut, then the alarm is sounded. In the event that a switch fails and a false alarm is sounded, the entire alarm system is typically shut down until the faulty switch can be found and repaired or replaced. It is, therefore, desirable to have a switch that can be repaired or replaced in a minimum amount of time.
Currently, it is known to reduce the risk of false alarms by using a pair of switches at each station. The pair of switches, which are usually of a pushbutton type, are placed opposite one another within a single case or housing such that a person would normally have to use two fingers to activate the alarm. In this manner, if one switch is accidentally pushed, the alarm will not sound. Such switches and their associated housing are generally referred to as xe2x80x9ctwo-finger switches.xe2x80x9d If a two-finger switch becomes defunct, technicians generally prefer to replace both switches in order to quickly restore the alarm system to its activated state. This eliminates the time required to determine which of the switches is actually broken.
U.S. Pat. No. 5,229,545 describes a switch holder housing for an alarm system two finger switch. The holder includes a cover and a planar base. The cover has a number of side panels, one of which includes a three-sided rectangular opening. When assembled, the opening receives the switch. Mounting means are included to connect the cover with the base. The base includes an abutment member that extends upwardly from the base""s upper surface. The switch is held in position within the opening by the abutment member when the cover is mounted to the base. Wiring is soldered between the two switches. Incoming wiring is soldered to each switch as well.
The ""545 device has a number of disadvantages. When replacing a worn switch, the existing wiring must be cut from the worn switch and resoldered to a new switch pair. The connected pair is then inserted into the housing and reinstalled at the work surface. The ""545 device is difficult to repair because connecting incoming wiring to a switch generally takes two hands, leaving no hands available to hold the switch itself. Alternatively, the installer can insert the new switch pairs into the openings of the cover prior to reconnecting the incoming wiring. This approach stabilizes the switches; however, it makes it much more difficult for the installer to resolder the connections because the switches are cramped within the inner volume of the cover.
Further, the ""545 device, as well as a number of other known two-finger switches, require a technician to fully understand the customer""s underlying alarm system in order to be able to properly install the replacement switches. Some alarm systems operate in a normally closed configuration (as described above, in which current is always provided in a switch, and the alarm system is tripped when the current is interrupted). These setups are referred to as xe2x80x9cnormally closedxe2x80x9d. Others operate in a normally open configuration (in which current is not normally present in a switch, and the alarm system is tripped when current is present). These setups are referred to as xe2x80x9cnormally openxe2x80x9d. In addition, two-finger switches can be used to activate two separate aspects of the alarm system. For example, pressing one switch may activate a camera, while simultaneously pressing both switches may activate a silent alarm. The wiring to these different functions can be either both normally open, both normally closed, or one open and the other closed. As one can appreciate, this requires the technician to understand the alarm system and take care in installing the switch correctly, both of which are disadvantageously time consuming.
Thus, a need exists for an improved switch arrangement. Ideally, such a switch would be easy to manufacture, easy to install, and easy to replace. The present invention is directed to fulfilling these needs and others as described below.
In accordance with the teachings of the present invention, a switch assembly is described having one or more switches and a holder. The switches are preferably of a pushbutton type having an outwardly extending flange. The holder includes a cover and base with a pair of upright arms. The cover includes a three-sided opening. As assembled, the upright arms receive a switch and the combination is received in the three-sided opening of the cover.
In accordance with aspects of this invention, one embodiment is described in which the switch includes a protrusion extending from its main body. As assembled, at least portions of the arms are longitudinally maintained between the protrusion and the flange. In another embodiment, the pair of arms each includes an inwardly oriented channel. As assembled, the switch flange is held in the arm channels.
In accordance with other aspects of this invention, a switch subassembly is described for connection to incoming electrical wiring in a two-finger switch. The subassembly includes a pair of circuit boards. A switch and a quick-disconnect unit are attached to each board. Interconnecting wiring is mounted between the circuit boards, so that no further wiring between the switches is necessary when installing the subassembly in a switch holder.